// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#nullable disable

namespace Microsoft.DotNet.Cli.Telemetry;

internal class CIEnvironmentDetectorForTelemetry : ICIEnvironmentDetector
{
    // Systems that provide boolean values only, so we can simply parse and check for true
    private static readonly string[] _booleanVariables = [
        // Azure Pipelines - https://docs.microsoft.com/en-us/azure/devops/pipelines/build/variables#system-variables-devops-services
        "TF_BUILD",
        // GitHub Actions - https://docs.github.com/en/actions/learn-github-actions/environment-variables#default-environment-variables
        "GITHUB_ACTIONS",
        // AppVeyor - https://www.appveyor.com/docs/environment-variables/
        "APPVEYOR",
        // A general-use flag - Many of the major players support this: AzDo, GitHub, GitLab, AppVeyor, Travis CI, CircleCI.
        // Given this, we could potentially remove all of these other options?
        "CI",
        // Travis CI - https://docs.travis-ci.com/user/environment-variables/#default-environment-variables
        "TRAVIS",
        // CircleCI - https://circleci.com/docs/2.0/env-vars/#built-in-environment-variables
        "CIRCLECI",
    ];

    // Systems where every variable must be present and not-null before returning true
    private static readonly string[][] _allNotNullVariables = [
        // AWS CodeBuild - https://docs.aws.amazon.com/codebuild/latest/userguide/build-env-ref-env-vars.html
        ["CODEBUILD_BUILD_ID", "AWS_REGION"],
        // Jenkins - https://github.com/jenkinsci/jenkins/blob/master/core/src/main/resources/jenkins/model/CoreEnvironmentContributor/buildEnv.groovy
        ["BUILD_ID", "BUILD_URL"],
        // Google Cloud Build - https://cloud.google.com/build/docs/configuring-builds/substitute-variable-values#using_default_substitutions
        ["BUILD_ID", "PROJECT_ID"]
    ];

    // Systems where the variable must be present and not-null
    private static readonly string[] _ifNonNullVariables = [
        // TeamCity - https://www.jetbrains.com/help/teamcity/predefined-build-parameters.html#Predefined+Server+Build+Parameters
        "TEAMCITY_VERSION",
        // JetBrains Space - https://www.jetbrains.com/help/space/automation-environment-variables.html#general
        "JB_SPACE_API_URL"
    ];

    public bool IsCIEnvironment()
    {
        foreach (var booleanVariable in _booleanVariables)
        {
            if (bool.TryParse(Environment.GetEnvironmentVariable(booleanVariable), out bool envVar) && envVar)
            {
                return true;
            }
        }

        foreach (var variables in _allNotNullVariables)
        {
            if (variables.All((variable) => !string.IsNullOrEmpty(Environment.GetEnvironmentVariable(variable))))
            {
                return true;
            }
        }

        foreach (var variable in _ifNonNullVariables)
        {
            if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable(variable)))
            {
                return true;
            }
        }

        return false;
    }
}
